The present invention relates to a refrigerator having a deep-temperature freezing chamber.
A typical refrigerator is a household appliance that stores food at a low temperature and can be divided into a refrigerating chamber and a freezing chamber depending on the temperature of the food stored in the refrigerator. Typically, the refrigerating chamber generally keeps a temperature of 3° C. to 4° C., and the freezing chamber generally keeps a temperature of about −20° C.
A freezing chamber with a temperature of about −20° C. is a space in which food is kept in a state of being frozen and is often used by consumers to store food for a long period of time. However, in the existing freezing chamber which keeps a temperature of about −20° C., there are problems that when the meat or seafood is frozen and the water in the cell is frozen, the water is discharged out of the cell and the cell is destroyed, and thus the original taste thereof is lost or texture thereof is changed when the meat or the seafood is cooked after thawing.
On the other hand, there are advantages that when meat, seafood, or the like is frozen, a temperature range of the freezing point where the ice forms in the cell is rapidly passed and the cooling thereof is done, the cell destruction can be minimized and, the quality and the texture of the meat are freshly renewed or reproduced and thus cooking is delicious, after thawing.
Because of this, high-end restaurants use deep-temperature freezers that can rapidly freeze meat, fish, seafood, or the like. However, unlike restaurants that need to preserve large quantities of food, it is unlikely to purchase deep-temperature freezers such as those used in restaurants since it is not always necessary to use a deep-temperature freezer in regular homes.
However, as the quality of life has improved, consumers' desire to eat more delicious foods has become stronger, and thus consumers who want to use deep-temperature freezers have increased.
In order to meet the needs of such consumers, there has been developed a household refrigerator in which a deep-temperature freezing chamber is installed in a portion of the freezing chamber. It is preferable that the deep-temperature freezing chamber satisfies a temperature of about −50° C., and such a cryogenic temperature is a temperature that cannot be reached only by a refrigeration cycle using a typical refrigerant.
Accordingly, household refrigerators are developed in which includes a separate deep-temperature freezing chamber in which the food is cooled to a temperature of −20° C. by a refrigeration cycle and is cooled to a temperature lower than −20° C. by a thermoelectric element (TEE).
However, since the difference in temperature between a freezing chamber of −20° C. and a deep-temperature freezing chamber of −50° C. is considerably large, if structures such as insulation, defrosting, and cold supply which is applied to a design of the existing freezing chamber are applied to the deep-temperature freezing chamber, as it were, it is not easy to implement a temperature of −50° C.
On the other hand, in the space of the deep-temperature freezing chamber, there is a cooling portion which is cooler than the deep-temperature freezing chamber and if condensation occurs in this portion, the condensation needs to be removed. However, since the temperature inside the deep-temperature freezing chamber is much lower than the temperature of the freezing chamber, which is the space outside the deep-temperature freezing chamber, as well as the melting point of water, it is unlikely to make defrosting smooth.
In addition, when excessive heating of the cooling portion of the deep-temperature freezing chamber for defrosting, since the excessive heating thereof may adversely affect the environment of the deep-temperature freezing chamber, a technique that can minimize the adverse effect is required.
In addition, a phenomenon is also an evitable problem which the defrost water is re-frozen by exposing the defrost water to the cryogenic environment in a process of discharging the defrost water generated by defrosting in the deep-temperature freezing chamber. In addition, it is also very difficult to implement a structure for discharging the defrost water.
Also, the cryogenic environment of the deep-temperature freezing chamber generates an excessive negative pressure inside the deep-temperature freezing chamber and a structure for relieving the negative pressure while minimizing the cold loss in the deep-temperature freezing chamber is required.
In addition, when the deep-temperature freezing chamber is provided while occupying the space of the freezing chamber itself, it is necessary to minimize the volume occupied by the structure for cooling and circulating the cooling air in the deep-temperature freezing chamber since a decrease in the volume capacity of the freezing chamber has to be minimized.
In particular, in a case where a cryogenic temperature is implemented by using a thermoelectric element, heat exchange is generated smoothly on both the heat absorption side and the heat generation side of the thermoelectric element, and the cooling air cooled through heat exchange on the heat absorption side has to be circulated smoothly, and heat exchange loss or flow loss shall not be generated while having a simple structure as possible.
In addition, there is a concern that the flow rate and the pressure distribution of the grill pan assembly structure of the related art may change, and the freezing of the freezing chamber may not be performed smoothly, due to the volume occupied by the thermoelectric element and the components relating thereto which are installed to implement the cryogenic temperature.